White and red blinking light moving across horizon, slowing down to a stop, then vanishing.

I was at the Portland, Maine fireworks show with my aunt and her friend and I looked out towards the ocean. I saw what I thought to be a jet coming to land at the nearby airport moving across the horizon where the ocean and the sky meet. It was a blinking red and white light, like an airplanes rotating beacon light. It was moving at normal airplane speed but then it started slowing down, and then it came to an almost complete stop. I pointed it out to my aunt, and she couldn't see it really well, then I looked back and it had vanished.